Hi,
You need to play with your slicer and write your custom Gcode for the tool change,
And you need to use one of the Smoothie PWM capable spare pin(look for example how the BL-Touch probe on smoothie is driven( the same as a servo which is using a 5volts pwm signal).
You can find the setup in the documentation, is clearly explayned.
Last thing:
I would not recommend you to use the servo as it is in the drawing, the pwm signal is unstable, and even a small variation will made your extruder head moving, so you may will consider to use the servo just for put in place the nozzle but with a final lock in place(magnetic ball or so on) to be sure that both nozzles will print always on the same track.
:-)) Regards

Thank for you help
For the stability, I planned to add at a ball pressure screw on the center front if it's necessary.

To drive the actuator there is this kind of electronic card able to manage a dual Position only with a binary output signal. I hope this will be reliable but I can also drive the actuator directly with the mother card.